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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2011 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: IPv4Util.html 689 2013-06-28 19:22:16Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.dellroad.stuff.net;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.net.Inet4Address;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.net.InetAddress;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import java.net.UnknownHostException;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import java.util.regex.Matcher;<a name="line.13"></a>
<span class="sourceLineNo">014</span>import java.util.regex.Pattern;<a name="line.14"></a>
<span class="sourceLineNo">015</span><a name="line.15"></a>
<span class="sourceLineNo">016</span>/**<a name="line.16"></a>
<span class="sourceLineNo">017</span> * Utility methods for working with IPv4 addresses and netmasks.<a name="line.17"></a>
<span class="sourceLineNo">018</span> */<a name="line.18"></a>
<span class="sourceLineNo">019</span>public final class IPv4Util {<a name="line.19"></a>
<span class="sourceLineNo">020</span><a name="line.20"></a>
<span class="sourceLineNo">021</span>    public static final int MIN_VALID_NETMASK_WIDTH = 8;<a name="line.21"></a>
<span class="sourceLineNo">022</span>    public static final int MAX_VALID_NETMASK_WIDTH = 30;<a name="line.22"></a>
<span class="sourceLineNo">023</span><a name="line.23"></a>
<span class="sourceLineNo">024</span>    private IPv4Util() {<a name="line.24"></a>
<span class="sourceLineNo">025</span>    }<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>    /**<a name="line.27"></a>
<span class="sourceLineNo">028</span>     * Convert from 32-bit integer representation.<a name="line.28"></a>
<span class="sourceLineNo">029</span>     */<a name="line.29"></a>
<span class="sourceLineNo">030</span>    public static Inet4Address toAddress(int address) {<a name="line.30"></a>
<span class="sourceLineNo">031</span>        return IPv4Util.toAddress(new byte[] {<a name="line.31"></a>
<span class="sourceLineNo">032</span>            (byte)((address &gt;&gt; 24) &amp; 0xff),<a name="line.32"></a>
<span class="sourceLineNo">033</span>            (byte)((address &gt;&gt; 16) &amp; 0xff),<a name="line.33"></a>
<span class="sourceLineNo">034</span>            (byte)((address &gt;&gt; 8) &amp; 0xff),<a name="line.34"></a>
<span class="sourceLineNo">035</span>            (byte)(address &amp; 0xff),<a name="line.35"></a>
<span class="sourceLineNo">036</span>        });<a name="line.36"></a>
<span class="sourceLineNo">037</span>    }<a name="line.37"></a>
<span class="sourceLineNo">038</span><a name="line.38"></a>
<span class="sourceLineNo">039</span>    /**<a name="line.39"></a>
<span class="sourceLineNo">040</span>     * Convert to 32-bit integer representation.<a name="line.40"></a>
<span class="sourceLineNo">041</span>     */<a name="line.41"></a>
<span class="sourceLineNo">042</span>    public static int toInt32(Inet4Address address) {<a name="line.42"></a>
<span class="sourceLineNo">043</span>        byte[] bytes = address.getAddress();<a name="line.43"></a>
<span class="sourceLineNo">044</span>        return ((bytes[0] &amp; 0xff) &lt;&lt; 24)<a name="line.44"></a>
<span class="sourceLineNo">045</span>             | ((bytes[1] &amp; 0xff) &lt;&lt; 16)<a name="line.45"></a>
<span class="sourceLineNo">046</span>             | ((bytes[2] &amp; 0xff) &lt;&lt; 8)<a name="line.46"></a>
<span class="sourceLineNo">047</span>             | (bytes[3] &amp; 0xff);<a name="line.47"></a>
<span class="sourceLineNo">048</span>    }<a name="line.48"></a>
<span class="sourceLineNo">049</span><a name="line.49"></a>
<span class="sourceLineNo">050</span>    /**<a name="line.50"></a>
<span class="sourceLineNo">051</span>     * Convert to an unsigned 32-bit integer representation within a 64-bit long.<a name="line.51"></a>
<span class="sourceLineNo">052</span>     */<a name="line.52"></a>
<span class="sourceLineNo">053</span>    public static long toUInt32(Inet4Address address) {<a name="line.53"></a>
<span class="sourceLineNo">054</span>        return toInt32(address) &amp; 0x00000000ffffffffL;<a name="line.54"></a>
<span class="sourceLineNo">055</span>    }<a name="line.55"></a>
<span class="sourceLineNo">056</span><a name="line.56"></a>
<span class="sourceLineNo">057</span>    /**<a name="line.57"></a>
<span class="sourceLineNo">058</span>     * Convert raw bytes to an {@link Inet4Address}.<a name="line.58"></a>
<span class="sourceLineNo">059</span>     *<a name="line.59"></a>
<span class="sourceLineNo">060</span>     * @throws IllegalArgumentException if array does not have length four<a name="line.60"></a>
<span class="sourceLineNo">061</span>     */<a name="line.61"></a>
<span class="sourceLineNo">062</span>    public static Inet4Address toAddress(byte[] bytes) {<a name="line.62"></a>
<span class="sourceLineNo">063</span>        if (bytes.length != 4)<a name="line.63"></a>
<span class="sourceLineNo">064</span>            throw new IllegalArgumentException("array has length " + bytes.length + " != 4");<a name="line.64"></a>
<span class="sourceLineNo">065</span>        try {<a name="line.65"></a>
<span class="sourceLineNo">066</span>            return (Inet4Address)InetAddress.getByAddress(toString(bytes), bytes);<a name="line.66"></a>
<span class="sourceLineNo">067</span>        } catch (UnknownHostException e) {<a name="line.67"></a>
<span class="sourceLineNo">068</span>            throw new RuntimeException("unexpected exception", e);<a name="line.68"></a>
<span class="sourceLineNo">069</span>        }<a name="line.69"></a>
<span class="sourceLineNo">070</span>    }<a name="line.70"></a>
<span class="sourceLineNo">071</span><a name="line.71"></a>
<span class="sourceLineNo">072</span>    /**<a name="line.72"></a>
<span class="sourceLineNo">073</span>     * Convert an IPv4 address to string representation.<a name="line.73"></a>
<span class="sourceLineNo">074</span>     *<a name="line.74"></a>
<span class="sourceLineNo">075</span>     * @throws IllegalArgumentException if array does not have length four<a name="line.75"></a>
<span class="sourceLineNo">076</span>     */<a name="line.76"></a>
<span class="sourceLineNo">077</span>    public static String toString(Inet4Address address) {<a name="line.77"></a>
<span class="sourceLineNo">078</span>        return IPv4Util.toString(address.getAddress());<a name="line.78"></a>
<span class="sourceLineNo">079</span>    }<a name="line.79"></a>
<span class="sourceLineNo">080</span><a name="line.80"></a>
<span class="sourceLineNo">081</span>    /**<a name="line.81"></a>
<span class="sourceLineNo">082</span>     * Convert a network address (IPv4 base address and netmask) to string representation.<a name="line.82"></a>
<span class="sourceLineNo">083</span>     *<a name="line.83"></a>
<span class="sourceLineNo">084</span>     * @throws IllegalArgumentException if array does not have length four<a name="line.84"></a>
<span class="sourceLineNo">085</span>     */<a name="line.85"></a>
<span class="sourceLineNo">086</span>    public static String toString(Inet4Address address, Inet4Address netmask) {<a name="line.86"></a>
<span class="sourceLineNo">087</span>        return IPv4Util.toString(address) + "/" + IPv4Util.getWidth(netmask);<a name="line.87"></a>
<span class="sourceLineNo">088</span>    }<a name="line.88"></a>
<span class="sourceLineNo">089</span><a name="line.89"></a>
<span class="sourceLineNo">090</span>    private static String toString(byte[] bytes) {<a name="line.90"></a>
<span class="sourceLineNo">091</span>        assert bytes.length == 4;<a name="line.91"></a>
<span class="sourceLineNo">092</span>        return (bytes[0] &amp; 0xff) + "." + (bytes[1] &amp; 0xff) + "." + (bytes[2] &amp; 0xff) + "." + (bytes[3] &amp; 0xff);<a name="line.92"></a>
<span class="sourceLineNo">093</span>    }<a name="line.93"></a>
<span class="sourceLineNo">094</span><a name="line.94"></a>
<span class="sourceLineNo">095</span>    /**<a name="line.95"></a>
<span class="sourceLineNo">096</span>     * Convert from string representation.<a name="line.96"></a>
<span class="sourceLineNo">097</span>     *<a name="line.97"></a>
<span class="sourceLineNo">098</span>     * @throws IllegalArgumentException if string is not an IP address<a name="line.98"></a>
<span class="sourceLineNo">099</span>     */<a name="line.99"></a>
<span class="sourceLineNo">100</span>    public static Inet4Address fromString(String string) {<a name="line.100"></a>
<span class="sourceLineNo">101</span>        String bytepat = "([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])";<a name="line.101"></a>
<span class="sourceLineNo">102</span>        Pattern pattern = Pattern.compile(bytepat + "\\." + bytepat + "\\." + bytepat + "\\." + bytepat);<a name="line.102"></a>
<span class="sourceLineNo">103</span>        Matcher matcher = pattern.matcher(string);<a name="line.103"></a>
<span class="sourceLineNo">104</span>        if (!matcher.matches())<a name="line.104"></a>
<span class="sourceLineNo">105</span>            throw new IllegalArgumentException("invalid IP address: " + string);<a name="line.105"></a>
<span class="sourceLineNo">106</span>        return toAddress(new byte[] {<a name="line.106"></a>
<span class="sourceLineNo">107</span>          (byte)Integer.parseInt(matcher.group(1)),<a name="line.107"></a>
<span class="sourceLineNo">108</span>          (byte)Integer.parseInt(matcher.group(2)),<a name="line.108"></a>
<span class="sourceLineNo">109</span>          (byte)Integer.parseInt(matcher.group(3)),<a name="line.109"></a>
<span class="sourceLineNo">110</span>          (byte)Integer.parseInt(matcher.group(4))<a name="line.110"></a>
<span class="sourceLineNo">111</span>        });<a name="line.111"></a>
<span class="sourceLineNo">112</span>    }<a name="line.112"></a>
<span class="sourceLineNo">113</span><a name="line.113"></a>
<span class="sourceLineNo">114</span>    /**<a name="line.114"></a>
<span class="sourceLineNo">115</span>     * Get netmask width.<a name="line.115"></a>
<span class="sourceLineNo">116</span>     *<a name="line.116"></a>
<span class="sourceLineNo">117</span>     * @return a value between zero and 32 (inclusive)<a name="line.117"></a>
<span class="sourceLineNo">118</span>     * @throws IllegalArgumentException if the value is not a valid CIDR netmask<a name="line.118"></a>
<span class="sourceLineNo">119</span>     */<a name="line.119"></a>
<span class="sourceLineNo">120</span>    public static int getWidth(Inet4Address netmask) {<a name="line.120"></a>
<span class="sourceLineNo">121</span>        int mask = toInt32(netmask);<a name="line.121"></a>
<span class="sourceLineNo">122</span>        if (mask == 0)<a name="line.122"></a>
<span class="sourceLineNo">123</span>            return 0;<a name="line.123"></a>
<span class="sourceLineNo">124</span>        for (int shift = 0; shift &lt; 32; shift++) {<a name="line.124"></a>
<span class="sourceLineNo">125</span>            if (mask == (~0 &lt;&lt; shift))<a name="line.125"></a>
<span class="sourceLineNo">126</span>                return 32 - shift;<a name="line.126"></a>
<span class="sourceLineNo">127</span>        }<a name="line.127"></a>
<span class="sourceLineNo">128</span>        throw new IllegalArgumentException("invalid netmask " + netmask);<a name="line.128"></a>
<span class="sourceLineNo">129</span>    }<a name="line.129"></a>
<span class="sourceLineNo">130</span><a name="line.130"></a>
<span class="sourceLineNo">131</span>    /**<a name="line.131"></a>
<span class="sourceLineNo">132</span>     * Determine if the given address is a valid CIDR netmask.<a name="line.132"></a>
<span class="sourceLineNo">133</span>     * The netmask must have a width between 8 and 30 (inclusive).<a name="line.133"></a>
<span class="sourceLineNo">134</span>     */<a name="line.134"></a>
<span class="sourceLineNo">135</span>    public static boolean isValidNetmask(Inet4Address netmask) {<a name="line.135"></a>
<span class="sourceLineNo">136</span>        try {<a name="line.136"></a>
<span class="sourceLineNo">137</span>            int width = getWidth(netmask);<a name="line.137"></a>
<span class="sourceLineNo">138</span>            return width &gt;= MIN_VALID_NETMASK_WIDTH &amp;&amp; width &lt;= MAX_VALID_NETMASK_WIDTH;<a name="line.138"></a>
<span class="sourceLineNo">139</span>        } catch (IllegalArgumentException e) {<a name="line.139"></a>
<span class="sourceLineNo">140</span>            return false;<a name="line.140"></a>
<span class="sourceLineNo">141</span>        }<a name="line.141"></a>
<span class="sourceLineNo">142</span>    }<a name="line.142"></a>
<span class="sourceLineNo">143</span><a name="line.143"></a>
<span class="sourceLineNo">144</span>    /**<a name="line.144"></a>
<span class="sourceLineNo">145</span>     * Get netmask with the given width.<a name="line.145"></a>
<span class="sourceLineNo">146</span>     *<a name="line.146"></a>
<span class="sourceLineNo">147</span>     * @throws IllegalArgumentException if width is less than zero or greater than 32<a name="line.147"></a>
<span class="sourceLineNo">148</span>     */<a name="line.148"></a>
<span class="sourceLineNo">149</span>    public static Inet4Address getNetmaskForWidth(int width) {<a name="line.149"></a>
<span class="sourceLineNo">150</span>        if (width &lt; 0 || width &gt; 32)<a name="line.150"></a>
<span class="sourceLineNo">151</span>            throw new IllegalArgumentException("invalid netmask width " + width);<a name="line.151"></a>
<span class="sourceLineNo">152</span>        return toAddress(~0 &lt;&lt; (32 - width));<a name="line.152"></a>
<span class="sourceLineNo">153</span>    }<a name="line.153"></a>
<span class="sourceLineNo">154</span><a name="line.154"></a>
<span class="sourceLineNo">155</span>    /**<a name="line.155"></a>
<span class="sourceLineNo">156</span>     * Get the base address (all host bits zero) of the given IP network.<a name="line.156"></a>
<span class="sourceLineNo">157</span>     *<a name="line.157"></a>
<span class="sourceLineNo">158</span>     * @param address any IP address on the network<a name="line.158"></a>
<span class="sourceLineNo">159</span>     * @param netmask the netmask of the network<a name="line.159"></a>
<span class="sourceLineNo">160</span>     * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.160"></a>
<span class="sourceLineNo">161</span>     */<a name="line.161"></a>
<span class="sourceLineNo">162</span>    public static Inet4Address getBaseAddress(Inet4Address address, Inet4Address netmask) {<a name="line.162"></a>
<span class="sourceLineNo">163</span>        int addr = toInt32(address);<a name="line.163"></a>
<span class="sourceLineNo">164</span>        int width = getWidth(netmask);<a name="line.164"></a>
<span class="sourceLineNo">165</span>        addr &amp;= ~0 &lt;&lt; (32 - width);<a name="line.165"></a>
<span class="sourceLineNo">166</span>        return toAddress(addr);<a name="line.166"></a>
<span class="sourceLineNo">167</span>    }<a name="line.167"></a>
<span class="sourceLineNo">168</span><a name="line.168"></a>
<span class="sourceLineNo">169</span>    /**<a name="line.169"></a>
<span class="sourceLineNo">170</span>     * Get the broadcast address (all host bits one) of the given IP network.<a name="line.170"></a>
<span class="sourceLineNo">171</span>     *<a name="line.171"></a>
<span class="sourceLineNo">172</span>     * @param address any IP address on the network<a name="line.172"></a>
<span class="sourceLineNo">173</span>     * @param netmask the netmask of the network<a name="line.173"></a>
<span class="sourceLineNo">174</span>     * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.174"></a>
<span class="sourceLineNo">175</span>     */<a name="line.175"></a>
<span class="sourceLineNo">176</span>    public static Inet4Address getBroadcastAddress(Inet4Address address, Inet4Address netmask) {<a name="line.176"></a>
<span class="sourceLineNo">177</span>        int addr = toInt32(address);<a name="line.177"></a>
<span class="sourceLineNo">178</span>        int width = getWidth(netmask);<a name="line.178"></a>
<span class="sourceLineNo">179</span>        addr |= ~(~0 &lt;&lt; (32 - width));<a name="line.179"></a>
<span class="sourceLineNo">180</span>        return toAddress(addr);<a name="line.180"></a>
<span class="sourceLineNo">181</span>    }<a name="line.181"></a>
<span class="sourceLineNo">182</span><a name="line.182"></a>
<span class="sourceLineNo">183</span>    /**<a name="line.183"></a>
<span class="sourceLineNo">184</span>     * Determine if the given address lives on the given network.<a name="line.184"></a>
<span class="sourceLineNo">185</span>     *<a name="line.185"></a>
<span class="sourceLineNo">186</span>     * @param address IP address in question<a name="line.186"></a>
<span class="sourceLineNo">187</span>     * @param network network address<a name="line.187"></a>
<span class="sourceLineNo">188</span>     * @param netmask network netmask<a name="line.188"></a>
<span class="sourceLineNo">189</span>     * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.189"></a>
<span class="sourceLineNo">190</span>     */<a name="line.190"></a>
<span class="sourceLineNo">191</span>    public static boolean isOnNetwork(Inet4Address address, Inet4Address network, Inet4Address netmask) {<a name="line.191"></a>
<span class="sourceLineNo">192</span>        int addr1 = toInt32(address);<a name="line.192"></a>
<span class="sourceLineNo">193</span>        int addr2 = toInt32(network);<a name="line.193"></a>
<span class="sourceLineNo">194</span>        int width = getWidth(netmask);<a name="line.194"></a>
<span class="sourceLineNo">195</span>        int mask = ~0 &lt;&lt; (32 - width);<a name="line.195"></a>
<span class="sourceLineNo">196</span>        return (addr1 &amp; mask) == (addr2 &amp; mask);<a name="line.196"></a>
<span class="sourceLineNo">197</span>    }<a name="line.197"></a>
<span class="sourceLineNo">198</span><a name="line.198"></a>
<span class="sourceLineNo">199</span>    /**<a name="line.199"></a>
<span class="sourceLineNo">200</span>     * Determine if the given address is a valid host address on the given network.<a name="line.200"></a>
<span class="sourceLineNo">201</span>     * The address must lie on the given network and not equal either the base or broadcast addresses.<a name="line.201"></a>
<span class="sourceLineNo">202</span>     *<a name="line.202"></a>
<span class="sourceLineNo">203</span>     * @param address IP address in question<a name="line.203"></a>
<span class="sourceLineNo">204</span>     * @param network network address<a name="line.204"></a>
<span class="sourceLineNo">205</span>     * @param netmask network netmask<a name="line.205"></a>
<span class="sourceLineNo">206</span>     * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.206"></a>
<span class="sourceLineNo">207</span>     */<a name="line.207"></a>
<span class="sourceLineNo">208</span>    public static boolean isValidHostOnNetwork(Inet4Address address, Inet4Address network, Inet4Address netmask) {<a name="line.208"></a>
<span class="sourceLineNo">209</span>        return isOnNetwork(address, network, netmask)<a name="line.209"></a>
<span class="sourceLineNo">210</span>         &amp;&amp; !address.equals(getBaseAddress(network, netmask))<a name="line.210"></a>
<span class="sourceLineNo">211</span>         &amp;&amp; !address.equals(getBroadcastAddress(network, netmask));<a name="line.211"></a>
<span class="sourceLineNo">212</span>    }<a name="line.212"></a>
<span class="sourceLineNo">213</span>}<a name="line.213"></a>
<span class="sourceLineNo">214</span><a name="line.214"></a>




























































</pre>
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